1. Field of the Invention
The present invention generally relates to multilayer ceramic substrates and a method of forming the same.
2. Description of the Related Art
In traditional processing, a substrate contains signal or redistribution layers (which contain connections between different points) and voltage layers which look like mesh planes. Signal or redistribution vias pass through, without connecting to, the mesh plane. To the contrary, voltage vias connect with the mesh planes. Conventionally, each layer is fabricated separately which makes the process expensive and time consuming.
Ceramic packages for supporting semiconductor devices and the like include ceramic substrates with printed conductive stripes connected to the device and to input/output pins or other connections which are joined to boards or the like. While many techniques are known for forming such ceramic substrates, one of the most popular procedures for such fabrication involves the casting of what is termed a ceramic greensheet, personalizing (i.e., punching and screening) the greensheet, stacking it with other personalized greensheets and subsequently processing and firing of the stack of ceramic greensheets. The method of producing such multilayer ceramic (MLC) substrates for semiconductor packaging and other electronics applications is well known as illustrated in U.S. Pat. Nos. 4,234,367, 4,302,625 and 4,799,984, each of which is incorporated herein by reference.
In the traditional method of building MLC substrates, each personalized greensheet layer has a unique pattern which makes the personalization process expensive and time consuming. Accordingly, a new personalization process which is less expensive and time consuming is desired.
Building multi-layer personalized substrates is expensive and time consuming. For example, one part of the process involves applying the signal patterns to each layer (e.g., each greensheet) before lamination. A personalized via pattern must be drilled or punched for each layer as well. A process is needed that would improve the process time and reduce costs.
It is, therefore, an object of the present invention to provide a structure and method for personalizing a multi-layer substrate structure that includes supplying a generic layer having electrical features and altering the electrical features to produce a personalized layer of the multi-layer substrate. The altering includes selectively filling vias in the generic layer with conductive material and removing portions of electrical wiring on the generic layer. The process further includes supplying a second generic layer identical to the first generic layer and altering the electrical features of the second generic layer to produce a second personalized layer different than the first personalized layer. The altering changes the generic layer into a plurality of differently personalized layers. The generic layer includes a grid of vias and/or a pattern of wiring useful with a plurality of differently personalized layers.
Another embodiment of the invention is a process for personalizing a multi-layer substrate structure that includes supplying a layer having generic electrical features and altering the generic electrical features to produce a personalized layer of the multi-layer substrate. The altering includes selectively filling vias in the layer with conductive material and removing portions of electrical wiring on the layer. The process further includes supplying a second layer identical to the first layer and altering the generic electrical features of the second layer to produce a second personalized layer different than the first personalized layer. The altering changes the generic layer into a plurality of differently personalized layers. The layer includes a generic grid of vias and/or a generic pattern of wiring useful with a plurality of differently personalized layers.
Yet another embodiment of the invention is a multi-layer substrate structure that includes at least one layer having generic electrical features altered to personalize the layer. The electrical features include vias selectively filled with conductive material and/or a wiring pattern having portions selectively removed. The multi-layer substrate further includes a second layer similar to the first layer and having the generic electrical features altered differently than the first layer to personalize the second layer differently from the first layer. The layer can be changed into a plurality of differently personalized layers, and it includes a generic grid of vias and/or a generic pattern of wiring useful with a plurality of differently personalized layers.